The animal kingdom has a special place in American English. Financial markets can be bullish or bearish. A successful financial venture is a cash cow. The rat race is a dog-eat-dog environment, and horsing around will likely get a person thrown to the wolves. When describing a ferociously predatory individual, or trying to emphasize the danger of a situation, however, you can’t go wrong with sharks.

In the words of Kenny Rogers, one should never count one's money when one is sitting at the table. Credit: Ethan Miller/Getty Images

A card shark is an individual who is especially gifted at card games such as poker or blackjack. In a private game, an individual might feign ignorance, intentionally losing several hands to increase the stakes, before turning the tables on other players.

The world of pocket billards has produced another kind of shark. In the words of Robert Preston in The Music Man, you can spell trouble “with a capital ‘T’ and that rhymes with ‘P’ and that stands for ‘pool’.” But the world of the pool shark has a mystique that transcends musical condemnation. Depicted most memorably in The Hustler, the world of competitive pool spawned such memorable personalities as Willie Mosconi and Minnesota Fats.

Mr. Capone would like to offer you a very competitive interest rate. One that you can't refuse. Credit: Getty Images

“Jumping the shark” is a fairly recent shark-related addition to the lexicon. It is a term used to describe the exact moment at which a given narrative, be it fact or fiction, has definitely and irreversibly adopted a downward trajectory. The term is derived from an infamous Happy Days episode that featured Fonzie, a character that had previously been the virtual definition of cool, donning a pair of water skis and jumping over a shark. As terrible as it sounds, it made for a great in-joke on Arrested Development roughly a quarter-century later.